• Title/Summary/Keyword: PVDF 압전막

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Fabrication of PVDF Line Focus Ultrasonic Transducer and its Application I. Fabrication and Characteristics Evaluation (직선집속 PVDF 초음파트랜스듀서의 제작과 응용 I. 제작 및 특성평가)

  • Yoon Hyuck-joon;Ha Kang-Iyeol;Kim Moo-joon
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.387-390
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    • 1999
  • 누설탄성표면파(Leaky Surface Acoustic Wave : LSAW) 측정에 사용하는 것을 목적으로 PVBF 압전막을 이용하여 직선집속 초음파트랜스듀서를 제작하고 그 특성을 평가하였다. 제작은 한쪽 면이 원통형 구조를 갖는 구리, 알루미늄, 3mmPVC-에폭시 3가지 재료를 배면층으로 사용하여 각각에 PVDF를 부착시켜서 수중에 음파를 방사하도록 구성하였고, 특성평가는 임펄스응답 특성과 음장 특성으로 나누어서 평가하였다. 임펄스응답 특성은 제작한 3종류의 집속 초음파트랜스듀서에 대해 실험적으로 측정하고, Mason 등가회로1)를 이용한 이론적 해석결과와 비교하였다. 음장특성 측정실험은 구리를 배면체로 하여 제작한 집속 초음파트랜스듀서에 대해서 실시하였고, 그 이론적인 계산결과는 Raylelgh-Somme-rfeld 회 절이론2)을 도입하여 초점면에 형성되는 음압분포를 계산하는 것으로 얻어졌다. 실험은 펄스 초음파 송수기 및 $2{\mu}m/step$으로 이동하는 정밀 x-y-z 스테이지를 컴퓨터에 연결하여 자동 측정하는 것으로 수행되었는데, 그 결과는 이론 해석결과와 비교적 잘 일치하였다.

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Enhancement of Oxygen Transfer Efficiency Using Vibrating lung Assist Device in In-Vitro Fluid Flow (In-vitro 유동장에서 진동형 폐 보조장치를 이용한 산소전달 효율의 향상)

  • 권대규;김기범;이삼철;정경락;이성철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1332-1335
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    • 2003
  • This paper presents the enhancement of oxygen transfer efficiency using the vibrating intravascular lung assist device (VIVLAD) in in-vitro experiments for patients having chronic respiratory problems. The test section was a cylinder duct with the inner diameter of 30 mm. The flow rate was controlled by the pump and monitored by a built-in flow meter. The vibration apparatus was composed of a piezo-vibrator, a function generator. and a power amplifier. The direction of vibration was radial to the fluid flow. Gas flow rates of up to 6 l/min through the 120-cm-Jong hollow fibers have been achieved by exciting a piezo-vibrator. The output of PVDF sensor were investigated by various frequencies in VIVLAD. The experimental results showed that VIVLAD would be enhance oxygen transfer efficiency.

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Improvement of Piezoelectric Performance of the CNT/PVDF Composite Film by Enhancing Conductivity of the PEDOT:PSS Electrodes (PEDOT:PSS 전극의 전도도향상에 의한 CNT/PVDF 복합막의 압전성능 개선)

  • Lim, Young-Taek;Lee, Sunwoo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.11
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    • pp.716-719
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    • 2016
  • In this paper, we fabricated flexible CNT/PVDF (carbon nanotube / polyvinylidene fluoride) piezoelectric composite device with flexible poly(3,4-ethylenedioxythiophene) : polystyrene sulfonate (PEDOT:PSS) conducting polymer electrode using spray coating method. We tried to improve the piezoelectric performance from the CNT/PVDF composite film by enhancing electrical conductivity of the PEDOT:PSS electrodes. Electrical conductivity of the PEDOT:PSS electrode was enhanced by dipping it into the EG (ethylene glycol) solvent. Changes of chemical composition of the PEDOT:PSS electrode were analyzed with the dipping time by XPS (x-ray photoelectron spectroscopy) in terms of oxygen (O1s). Finally, Piezoelectric performances such as output voltage and current were measured with the dipping time. We found that enhanced electrical conductivity of the PEDOT:PSS electrodes resulted in improvement of the piezoelectric performance of the CNT/PVDF films.

A Study on the Characteristics of Mass Transfer in Hollow Fiber Membranes (중공사막에서의 물질전달 특성에 관한 연구)

  • 김기범;김종석;김종수;유일수;이왕로;김성종
    • Membrane Journal
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    • v.14 no.2
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    • pp.142-148
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    • 2004
  • This paper presents the enhancement of oxygen transfer efficiency using vibrating intravascular lung assist device (VIVLAD) for patients having chronic respiratory problems. The flow rate was controlled by the pump and monitored by a built-in flow meter. The vibration apparatus was composed of a piezo-actuator, a function generator, and a power amplifier. Gas flow rates of up to 6 L/min through the 120-cm-long hollow fibers have been achieved by exciting a piezo-actuator. The output PVDF sensor and FRF (frequency response function) were investigated by various frequency in VIVLAD. As a result, the maximum oxygen transfer rate was found to occur with maximum amplitude and the transfer of vibration to the hollow fiber membranes. It was excited by the frequency band of 35 Hz at various distilled water flow rates, and various module types.

Fabrication of a PMN-PZT needle hydrophone for photoacoustic imaging (광음향 영상화를 위한 PMN-PZT 바늘형 수중청음기 제작)

  • Fan, Xiaofeng;Cao, Yonggang;Ha, Kanglyeol;Kim, Moojoon;Kang, Hyun Wook;Oh, Junghwan
    • The Journal of the Acoustical Society of Korea
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    • v.35 no.3
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    • pp.175-182
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    • 2016
  • For application to several MHz photoacoustic imaging systems, a needle hydrophone was designed and fabricated by using PMN-PZT piezoelectric single crystal, and its characteristics were evaluated through comparison with a commercial PVDF(Polybinylidene Fluoride) hydrophone of which receiving sensitivity is known. The simulation using the KLM model results show that the peak receiving impulse response for $50{\Omega}$ terminating impedance of the fabricated hydrophone is -261.6 dB re $1V/{\mu}Pa$ and the frequency response is relatively flat over 2 ~ 12 MHz with fluctuation less than 5 dB. The measurement results using tone burst signals also show that it has higher (ave. 10.9 dB) sensitivity than the commercial hydrophone in 2 ~ 8 MHz, and the receiving sensitivity of $-255.8{\pm}2.8$ dB re $1V/{\mu}Pa$ was measured for the fabricated hydrophone. In addition, it is known that the photoacoustic signals and the image of a hair obtained by a mechanical scanned photoacoustic imaging system with the fabricated hydrophone were bigger and better than those obtained with the commercial hydrophone.

Fabrication of Two-Dimensional Array Hydrophones and Application to Ultrasonic Field Measurement (2차원 배열 수중청음기의 제작과 초음파 음장 측정에의 응용)

  • Ha, Kang-Lyeol;Kim, Moo-Joon;Kang, Gab-Joong;Hyun, Byung-Gook;Chae, Min-Ku;Imano, Gazuhiko
    • Journal of Sensor Science and Technology
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    • v.10 no.5
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    • pp.320-328
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    • 2001
  • Two-dimensional array hydrophones with $8{\times}8$ elements were designed and fabricated using the PVDF(Polyvinylidene fluoride) piezoelectric film, and the method and system for ultrasonic field measurement in several MHz $\sim$ tens of MHz band using the hydrophones was established. The characteristics of frequency response relating to the backing materials were analyzed with the Mason equivalent circuit for design, and the accuracy of ultrasonic field measurement relating to the sizes and kerfs of piezoelectric elements was discussed. Good results of the measurement of ultrasonic field formed by a circular plane transducer of 2.25MHz in water were obtained by the system with the array hydrophones.

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Bio-Piezoelectric Generator with Silk Fibroin Films Prepared by Dip-Coating Method (딥코팅에 의한 실크 피브로인막으로 제조한 바이오 압전발전기)

  • Kim, Min-Soo;Park, Sang-Shik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.34 no.6
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    • pp.487-494
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    • 2021
  • Piezoelectric generators use direct piezoelectric effects that convert mechanical energy into electrical energy. Many studies were attempted to fabricate piezoelectric generators using piezoelectrics such as ZnO, PZT, PVDF. However, these various inorganic/organic piezoelectric materials are not suitable for bio-implantable devices due to problems such as brittleness, toxicity, bio-incompatibility, bio-degradation. Thus, in this paper, piezoelectric generators were prepared using a silk fibroin film which is bio-compatible by dip-coating method. The silk fibroin films are a mixed state of silk I and silk II having stable β-sheet type structures and shows the d33 value of 8~10 pC/N. There was a difference in output voltages according to the thickness. The silk fibroin generators, coated 10 times and 20 times, revealed the power density of 16.07 μW/cm2 and 35.31 μW/cm2 using pushing tester, respectively. The silk fibroin generators are sensitive to various pressure levels, which may arise from body motions such as finger tapping, foot pressing, wrist shaking, etc. The silk fibroin piezoelectric generators with bio-compatibility shows the applicability as a low-power implantable piezoelectric generator, healthcare monitoring service, and biotherapy devices.